Electrolytic condenser



J.A.POWRA$ ELECTROLYTIC CONDENSER Aug. 27, 1935.

Filed March 26, 1954 2 Sheets-Sheet l Aer T INVENTOR TTORNEYJ 7, 1935. J. A. POITRAS 2,012,692

ELECTROLYTIC CONDENSER Filed March 26, 1934 2 Sheets-Sheet 2 INVENTOR yP/V A1 1]? 5 BY wfioRNEYls Patented Aug. 27, 1935 PATENT OFFICE ELECTROLYTIC CONDENSER Joseph A. l'oitras, Fort Lee, N. J., alsignor to Solar Manufacturing Corporation, a corpora:

tion of New York Application March 26, 1984, Serial No. 717,349 I Claims. (Cl. 175-415) My invention relates to electrolytic devices, such as electrolytic condensers, rectifiers or the like, comprising film-forming electrodes. These condensers are based upon the well known principie that when certain metals, as for instance densers are used for different purposes, one of their uses being in filter circuits to eliminate the alternating current ripples from rectified currents. However, it should be well understood that myinvention is not limited to such purposes and applications.

When electrolytic condensers are used for the above stated purpose, only one of the electrodes,

- namely, the anode, is required to be of film-forming metaL-preferredly aluminum. The cathode which, as a rule also forms the container of the condenser, is usually made of a metal which does not exhibit film formation, or at least, not to a marked extent, as such film formation on the cathode always results in a smaller initial capacity and larger power factor than desirable.

However, in practice it has been found that for economical reasons, in spite of this drawback, containers of aluminum which serve as cathodes are quite practical, and their shortcomings in the above mentioned respect may be overcome in different well-known ways, one of which is by chromium-plating the inside of the container where it comes into contact with the electrolyte. Such condensers with an aluminum container are far less expensive, and also much lighter than those made with a copper or nickel cathode.

The special improvement and novel features which characterize this invention are however not concerned with the formation of the aluminum cathode but with that of the aluminum anode and with a novel way of making an anode of great surfacecapacity, offering at the same time a free circulation path for the electrolyte at extremely low cost.

Many shapes and configurations have been tried out, to increase the electrolytic contact surface of the anode member, such for example, as a multiplicity of plates, spaced suitably apart, or corrugated tubes or a single plate wound in spiral form with the windings well separated from each other. In the latter and similar cases, however, it was. necessary to provide the spirally wound plate with many perforations to insure proper circulation and deaeration of the electrolyte, as the chemical action of the condenser develops considerable heat and gas. Such complications of form, however, involve much expense, waste of material and machine work, and the 5 present inventive concept is intended to show a simplification which obtains all advantages of former constructions without their drawbacks in v economical respects.

It is therefore among the objects of the present invention to provide an electrolytic condenser, made essentially of aluminum and of extremely simplified construction.

Another object of the invention is to provide a film-forming electrode of great surface capacity made from aluminum in ribbon form.

Another object is to provide an anode which can be formed from a continuous endless ribbon,

- by simply folding said ribbon upon itself.

Another object is to provide an anode, made of an endless ribbon, folded upon itself, which does not require any perforation to secure free circulation of the electrolyte.

A further object is to reinforce and stiffen this ribbon by running it through a rolling or beading machine, adapted to emboss the separate sections to be folded upon each other, with outstanding ribs.

A further object is to arrange this endless ribbon in such a form that the whole surface of it is exposed to the action of the electrolyte to the greatest advantage.

Another object is to provide a simplified construction of an anode terminal which can be made entirely from the endless ribbon itself.

Another object is to provide an improved construction of an insulating bushing which firmly holds the anodeterminal in the cathode container,

A further object is to provide adequate means for degasing the electrolytic condenser.

Other more specific objects and advantages of the device will appear as the nature of the improvements is better understood, the invention consisting substantially in the novel arrangemerit and correlation of instrumentalities herein fully described and illustrated in the accompanying drawings wherein similar reference characters are used to describe corresponding parts throughout the several views and then finally pointed out and specifically defined and indicated in the appended claims.

The disclosure made the basis of exemplifying the present inventive concept suggests a practical embodiment thereof, but the invention is not to be restricted to the exact details of this disclosure. and the latter therefore is to be understood from an illustrative, rather than a restrictive standpoint. It will be also understood that the various features of the present invention disclosed may be separately applicable despite their cooperation herein shown.

In the accompanying drawings- Fig. 1 is an elevational cross-section through a condenser made according to the principles of the invention, with the anode element and its terminal however shown in full;

Fig. 2 is a top view of the condenser;

Fig. 3 is a bottom view, showing the condenser terminals Fig. 4 is a horizontal cross section through the middle part of the condenser, illustrating how the sections of the ribbon, of which the anode is made, are spaced apart;

Fig. 5 is a fragmentary cross section through the upper part of the container and the anode elements, substantially along the line 5-! of Fig. 6 illustrates the shape of the anode ribbon, after bending and rebending it to form adjacent sections;

Fig. 7 shows in top view a portion of the endless ribbon, after it is run through the embossing rollers;

Fig. 8 is a longitudinal cross section along the line 2-8 of Fig. 7

Fig. 9 illustrates in which way the anode terminal is formed from the cut-off ends of the ribbon;

Fig. 10 is a sectional view through the lower part of a condenser, showing a. modified form of the terminal bushing;

Fig. 11 is an outside view of this lower part;

Fig. 12 illustrates another modification of such a bushing;

Fig. 13 is a further modification of the terminal bushing.

Referring more in detail to the separate views, the container forms one of the electrodes of the condenser and is of aluminum or some suitable metal, like copper or nickel which is not filmforming and non-corrosive. The electrolyte II is indicated as being liquid, although it may have a reduced fluidity, being in viscous form. Immersed in the electrolyte is a second electrode 22 of film-forming metal, for instance of aluminum. This is made from an endless ribbon, of, let us say, inch width and about the thickness of carton paper. A portion of such ribbon, flattened, out, is shown in Fig. 7. The dot and dash lines 22a indicate where the ribbon is to be bent forwards and backwards with more or less sharp comers,

' upon itself, so as to form a continuous zigzag band, illustrated in Fig. 6. In order to give this band more stiffness. so that the separate folds do not buckle and short-circuit each other, they are provided with ribs 22 which are extruded from the plane surface of the ribbon, alternately toward one side and the other, as Figs. 7 and 8 indicate. This can be accomplished very simply in well known manner by running one or more ribbons simultaneously through a pair of "embossing rollers" (not shown) which are provided with a series of protruding ridges and depressions, following each other alternatingly around the circumference of the rollers. The rollers are so matched that each protruding ridge on one roller fits into a depression on the other, and runs in a peripheral direction, at right angles to the axle.

The ribbons are so guided, when run between the rollers, that the embossed ribs are oi! the central line toward one edge (which afterwards becomes the outer edge of the assembled ribbon).

When the ribbon is thus embossed, bent and folded together into a zigzag band, a certain stack, containing enough material for one electrode, is out off, taking care to leave at each end an extra length 22b of material unbent, for a purpose presently to be described. Then the stack, closely folded together, is unfolded toward one side; i. e., looking at the ends of the stack, the folds are turned fanwise around one set of corners which are kept together while the opposite corners are spread apart. Thus the whole stack is converted into a cylindrical form, consisting of separate leaves which are radiating spokewise from an empty center, as is indicated at 24, and riveted together at 25. A regular binder clip 28 for a terminal leader may be attached thereby also. The enfolding of the ends has to be done in such a way that the terminal lies in the central axis of the condenser.

The folded anode element is further prevented.

from spreading by two encircling resilient (rubber) bands 21. If desired, these rubber bands may be seated in a peripheral series of notches 210 which can be punched out from the ribbon edges by a special machine, preparatory to running it These optional through the embossing machines. cutouts are shown in dotted lines in some sections of the band (Fig. '7). It is seen from Fig. 4 that after folding up the anode ribbon, all the extruded ribs are turned in one direction. The

outer container 20 can be shaped in different ways, but in the majority of cases it may be formed from a tubular blank, by contracting, pressing or spinning one end over a suitable mandrel into the proper form. Figs. 1, 10, 12 and 13 show different constructions of this end of the container.

One of the simplest ways is shown in the first figure. The tube is contracted by spinning to a smaller diameter and then drawn out to a tubular neck 28. Over this neck the sleeve 28 is slipped and the protruding end 30 is swaged out over the end of the sleeve by a spinning tool to retain the sleeve in place. The space between the terminal 22b, 28 and thetubular neck 22 is then filled by an insulating substance 2|, like rosin or asphalt which hardens when solidified, or soft rubber may be used as the insulating substance; i. e., in one form it may consist of two halves of a rubber plug which would be compressed over the terminal strip.

Generally the terminal end of the condenser is supported on a bracket or platform 22 in any suitable manner. If the outside of the sleeve is threaded, a hexagonal nut 33 can be used to clamp the sleeve and thereby the condenser to the platform which is apertured in a suitable manner. A washer 34 and a plate 35, adapted to serve as a binder post for attaching the oathode lead 26 to it, can be inserted around the neck piece 28 where it passes through the aperture in the platform.

An insulating washer 38, slotted for passing the anode terminal through it, is seated under the offset shoulder 24. Its main function is to tion it is also extruded inwardly to form a ringlike rib M, the mandrel over which thisfpart is spun, having a sharp edged groove into which the material is forced. Likewise, at two opposite points at the inner'rim of the bottom portion, the material is swaged outwardly to form two noses or keys 40 (Fig. 11), which fit into two corresponding keyways in the sleeve 29A, to be presently described.

The two concentric annular zones on the bottom portion, divided by the rib ll, serve as seats for two concentric gaskets 43 and M which form a hermetically sealed packing for the condenser. Over these gaskets and into the sleeve 29A is inserted a funnel-shaped thimble 45, having a substantially cylindrical neck, provided with annular corrugations 46. The protruding outer rim ll of this thimble is swaged over to retain the sleeve 29A in connection with the keys 40 fixedly in place. This sleeve is threaded on the outside for applying a nut and other supporting and terminal members to it, similar to those shown in Fig. 1. The space between the term nal 22b and the funnel shaped thimble 45 is likewise filled out by rubber, asphalt or rosin, the corrugations serving to retain the solidified insulating material securely in place.

The other modifications, shown in Figs. 12 and 13, differ from the one just described in some minor details to be specified hereafter, it being understood that the other details, not specially mentioned, but illustrated, are substantially identical with the foregoing.

According to Fig. 12, the lower .part of the tubular container 203 is not only contracted, but also recessed, to form a hexagonal dished recess 50 into which the corresponding hexagonal flange 5| of the sleeve 293 can be seated. This prevents any spontaneous dislocation of the latter, when assembled. The upper flange 53 of the thimble 52 is shaped to follow the inner contour of the container bottom, leaving only clearance enough to insert a rubber or cork gasket SI therebetween to form a liquid-tight packing. The protruding lower end of the thimble 52 is also swaged over the end of the sleeve 293, but a special gasket 55 can be inserted to serve as an additional airtight seal.

The last modification, shown in Fig. 13, diifers from the foregoing, in that the container and the sleevejon which the hexagonal nut 33 is threaded, is combined into an integral piece. If

the tube from which the container is made, is

too thin to turn a substantial thread on it, a special neck tube may be welded onto the contracted bottom of the tubular body which, especially in the case of copper or nickel, is not difllcult, or, in the case of aluminum, formed with extra thickness, by an extrusion process. Instead of two gaskets, as in the case shown in Fig. 10, only one (56) is employed.

It remains to be described how the upper end of the container is closed, in order to close it hermetically in an inexpensive and yet reliable manner.

A dished or cupped end member I is inserted into the open end of the tubular container 20. The outer flange 60a. of this member has an inward inclination so that the general shape .of this cupped member resembles a conical frustrum, though only slightly deviating from the cylindrical form. Theouter diameter of the bottom is equal to the inside diameter of the tubular member 20 and, after the cupped member 60 is inserted to its proper depth into the assembled container, the outer rim 201 of the container is tightened by spinning it toward the conical wall of the cupped member 60. At the same time the upper rim 60b is spun outwardly and crimped over the contracted rim .201- so as to form a tightly interlocking Joint with the latter. The middle portion of the cupped member 60 is raised to form a, cylindrical head 6| which has a central bigger opening and one or more small perforations 62 through which gas under pressure can escape. The gas holes are normally kept closed by a safety valve which may be of various constructions, and is shown and described in my copending application, filed March 26, 1934, under Serial Number 717,348 but for which no special patent protection is claimed here. These valves, as shown in Figs. 1 and 5, substantially comprise an annular soft rubber gasket 63 which covers the' gas holes 62, a mushroom-like lid 64 which is clamped over said gasket, and a saddle-shaped clasp 65 which is resil- :ently clamped against the inner side of the raised head 6i and coupled to the center of the lid by means of a rivet 66. The resilient cushion of the clasp may consist of a soft rubber ring 61a or a fine spring 611). In either case, when there is surplus gas pressure in the condenser, the gasket 63 together with the lid 64 is raised against the resiliency of rubber ring 61a or spring 61b to let the gas escape from under the gasket 63.

It is obvious from the foregoing description of my invention that the electrolytic condenser forming the subject matter of this application is notably and radically different and a decided improvement of prior-structures in that it is not a spirally wound or folded anode; that the anode has no rod to which it is riveted or welded, nor is there a special metal strap provided to which the anode itself has to be riveted or welded, but that nothing but the ribbon itself is used in making up the anode; likewise no perforations are necessary in the anode of my invention because it is so constructed that the electrolyte solution can come in contact with all parts of this anode and the inner walls of the can and a free path is provided for the solution between all points of the can and the anode at all times.

Not only does this construction allow a free path for the solution. which spirally-wound anodes do not permit; but it is a great improvement over the spirally-wound anodes which only allow a path up and down and then across by means of piercing holes into same while my new anode accomplishes this purpose in the most perfect manner by allowing the electrolyte to pass both up and down and crosswise freely between all points, thereby permitting an uninterrupted flow of solution, thus creating a wet electrolytic condenser of the most perfect'electrical characteristics. This perfection of electrical characteristics consists of lower power factor, all around efliciency and higher capacity per given area.

In accordance with the provisions of the patc-nt statute, I have described my invention, but I desire it understood that it is not confined to the particular form shown and described, the

same being merely illustrative, and that the invention can be carried out in other ways without departing from the spirit of my invention, and therefore I claim broadly the right to employ all equivalent instrumentalities coming within the scope of the appended claims, and by means of which, objects of my invention are attained and new results accomplished, as it is obvious that the particular embodiments herein shown and described are only some of many that can be employed to attain these objects and accomplish these results.

Having thus described my invention, what I claim and desire to secure by Letters Patent, is:

1. In a cylindrical electrolytic condenser, an anode electrode made of a single ribbon of filmiorming metal, bent back and forth in an annular zigzag course around the axis of the condenser, with the two ends joined together and insulatingly carried through the bottom oi the condenser to form a single terminal.

2. An electrolytic condenser comprising a. metal container for the electrolyte, said container adapted to form the cathode electrode,

and a single ribbon of film-forming metal, adapt-- ed to serve as anode electrode, said ribbon, wholly submerged by the electrolyte and insulatingly supported within the container and arranged in alternating spaced folds running in a longitudinal direction up and down around the axis of the container, the anode terminal connection being made through the bottom of the container and insulated therefrom.

3. In an electrolytic condenser, an anode electrode made of a single ribbon of film-forming metal, reinforced by a series of embossed ribs, aligned in a longitudinal direction, and parted from each other by short flat spaces, said ribbon bent alternately back and forth between the aforesaid flat spaces.

4. In an electrolytic condenser, an anode electrode made of a single ribbon of film-forming metal, bent back and forth in zigzag form, the separate iolds being reinforced by embossed longitudinal single ribs, placed only along the straight portions.

5. In an electrolytic condenser, the combination with a metal container for the electrolyte, adapted to form the cathode electrode, and an anode electrode, submerged by the electrolyte and consisting of a single ribbon of film-forming metal, non-conductively supported within said container and protruding from the bottom of said container in the form. of a terminal, integral with said ribbon; of a bushing inserted between said terminal and the inner wall of the container, said bushing provided with means to hold it within said container and with corrugations on its inside to retain any insulating material surrounding the terminal, in place.

6. An electrolytic condenser comprising a cylindrical metal container for the electrolyte, said container adapted to form the cathode electrode, and a single ribbon of film-forming metal, adapted to serve as anode electrode, said. ribbon insulatinglysupported within the electrolyte and arranged in alternating spaced'folds, slightly inclined and running in a longitudinal direction up and down around the axis of the container, with the bends running radially and the folds not touching each other on the inside and leavin a tree circular space in the center, so that the electrolyte solution can freely circulate.

7. In a cylindrical electrolytic condenser, a ribbon anode electrode folded up in one continuous up and down zlg-zag strip, following an annular path around the axis with the two ends brought together, thereby causing the entire anode to assume a cylindrical Ian shape with the two extensions, which formerly were the beginning and the end oi the ribbon, protruding through the bottom.

8. In an electrolytic condenser, the combination with an anode electrode and a metal container for the electrolyte, said container being contracted at the supporting end into a periorated flat bottom, provided with a protruding nose; of a tubular separate neck piece, provided with a recess fitting over said nose and adapted to serve as the cathode terminal, means to securely fasten said neck piece to the container, said means comprising a thimble fitted into said neck piece and protruding inwardly and outwardly beyond it, the inward end spun over the inside ot the fiat container bottom and the outward end swaged over the end of the neck piece, and

insulating means to secure the anode terminal within the thimble.

JOSEPH A. POITRAS. 

